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Kubernetes Ingress Support

Documentation/network/servicemesh/ingress.rst

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.. _gs_ingress:

Kubernetes Ingress Support

Cilium uses the standard Kubernetes Ingress_ resource definition, with an ingressClassName of cilium. This can be used for path-based routing and for TLS termination. For backwards compatibility, the kubernetes.io/ingress.class annotation with value of cilium is also supported.

.. Note::

The ingress controller creates a Service of LoadBalancer type, so
your environment will need to support this.

Cilium allows you to specify load balancer mode for the Ingress resource:

  • dedicated: The Ingress controller will create a dedicated loadbalancer for the Ingress.
  • shared: The Ingress controller will use a shared loadbalancer for all Ingress resources.

Each load balancer mode has its own benefits and drawbacks. The shared mode saves resources by sharing a single LoadBalancer config across all Ingress resources in the cluster, while the dedicated mode can help to avoid potential conflicts (e.g. path prefix) between resources.

.. Note::

It is possible to change the load balancer mode for an Ingress resource.
When the mode is changed, active connections to backends of the Ingress
may be terminated during the reconfiguration due to a new load balancer
IP address being assigned to the Ingress resource.

This is a step-by-step guide on how to enable the Ingress Controller in an existing K8s cluster with Cilium installed.

.. _Kubernetes Ingress: https://kubernetes.io/docs/concepts/services-networking/ingress/

Prerequisites #############

  • Cilium must be configured with the kube-proxy replacement, using kubeProxyReplacement=true. For more information, see :ref:kube-proxy replacement <kubeproxy-free>.
  • Cilium must be configured with the L7 proxy enabled using l7Proxy=true (enabled by default).
  • By default, the Ingress controller creates a Service of LoadBalancer type, so your environment will need to support this. Alternatively, you can change this to NodePort or, since Cilium 1.16+, directly expose the Cilium L7 proxy on the :ref:host network<gs_ingress_host_network_mode>.

.. include:: installation.rst

.. include:: ingress-reference.rst

Ingress Path Types and Precedence

The Ingress specification supports three types of paths:

  • Exact - match the given path exactly.
  • Prefix - match the URL path prefix split by /. The last path segment must match the whole segment - if you configure a Prefix path of /foo/bar, /foo/bar/baz will match, but /foo/barbaz will not.
  • ImplementationSpecific - Interpretation of the Path is up to the IngressClass. In Cilium's case, we define ImplementationSpecific to be "Regex", so Cilium will interpret any given path as a regular expression and program Envoy accordingly. Notably, some other implementations have ImplementationSpecific mean "Prefix", and in those cases, Cilium will treat the paths differently. (Since a path like /foo/bar contains no regex characters, when it is configured in Envoy as a regex, it will function as an Exact match instead).

When multiple path types are configured on an Ingress object, Cilium will configure Envoy with the matches in the following order:

#. Exact #. ImplementationSpecific (that is, regular expression) #. Prefix #. The / Prefix match has special handling and always goes last.

Within each of these path types, the paths are sorted in decreasing order of string length.

If you do use ImplementationSpecific regex support, be careful with using the * operator, since it will increase the length of the regex, but may match another, shorter option.

For example, if you have two ImplementationSpecific paths, /impl, and /impl.*, the second will be sorted ahead of the first in the generated config. But because * is in use, the /impl match will never be hit, as any request to that path will match the /impl.* path first.

See the :ref:Ingress Path Types <gs_ingress_path_types> for more information.

Supported Ingress Annotations

.. list-table:: :header-rows: 1

    • Name
    • Description
    • Default Value
    • ingress.cilium.io/loadbalancer-mode
    • | The loadbalancer mode for the ingress. | Allows a per ingress override | of the default set in the Helm value | ingressController.loadbalancerMode. | Applicable values are dedicated and | shared.
    • | dedicated | (from Helm chart)
    • ingress.cilium.io/loadbalancer-class
    • | The loadbalancer class for the ingress. | Only applicable when loadbalancer-mode is set to dedicated.
    • unspecified
    • ingress.cilium.io/service-type
    • | The Service type for dedicated Ingress. | Applicable values are LoadBalancer | and NodePort.
    • LoadBalancer
    • ingress.cilium.io/service-external-traffic-policy
    • | The Service externalTrafficPolicy for dedicated | Ingress. Applicable values are Cluster | and Local.
    • Cluster
    • ingress.cilium.io/insecure-node-port
    • | The NodePort to use for the HTTP Ingress. | Applicable only if ingress.cilium.io/service-type | is NodePort. If unspecified, a random | NodePort will be allocated by kubernetes.
    • unspecified
    • ingress.cilium.io/secure-node-port
    • | The NodePort to use for the HTTPS Ingress. | Applicable only if ingress.cilium.io/service-type | is NodePort. If unspecified, a random | NodePort will be allocated by kubernetes.
    • unspecified
    • ingress.cilium.io/host-listener-port
    • | The port to use for the Envoy listener on the host | network. Applicable and mandatory only for | dedicated Ingress and if :ref:host network mode<gs_ingress_host_network_mode> is | enabled.
    • 8080
    • ingress.cilium.io/tls-passthrough
    • | Enable TLS Passthrough mode for this Ingress. | Applicable values are enabled and disabled, | although boolean-style values will also be | accepted. | | Note that some conditions apply to TLS | Passthrough Ingresses, due to how | TLS Passthrough works: | * A host field must be set in the Ingress | * Default backends are ignored | * Rules with paths other than / are ignored | If all the rules in an Ingress are ignored for | these reasons, no Envoy config will be generated | and the Ingress will have no effect. | | Note that this annotation is analogous to | the ssl-passthrough on other Ingress | controllers.
    • disabled
    • ingress.cilium.io/force-https
    • | Enable enforced HTTPS redirects for this Ingress. | Applicable values are enabled and disabled, | although boolean-style values will also be | accepted. | | Note that if the annotation is not present, this | behavior will be controlled by the | enforce-ingress-https configuration | file setting (or ingressController.enforceHttps | in Helm). | | Any host with TLS config will have redirects to | HTTPS configured for each match specified in the | Ingress.
    • unspecified
    • ingress.cilium.io/request-timeout
    • | Request timeout in seconds for Ingress backend HTTP requests. | | Note that if the annotation is present, it will override | any value set by the ingress-default-request-timeout operator flag. | If neither is set, defaults to 0 (no limit)
    • 0

Additionally, cloud-provider specific annotations for the LoadBalancer Service are supported.

By default, annotations with values beginning with:

  • lbipam.cilium.io
  • nodeipam.cilium.io
  • service.beta.kubernetes.io
  • service.kubernetes.io
  • cloud.google.com

will be copied from an Ingress object to the generated LoadBalancer Service objects.

This setting is controlled by the Cilium Operator's ingress-lb-annotation-prefixes config flag, and can be configured in Cilium's Helm values.yaml using the ingressController.ingressLBAnnotationPrefixes setting.

Please refer to the Kubernetes documentation <https://kubernetes.io/docs/concepts/services-networking/service/#loadbalancer>_ for more details.

.. _gs_ingress_host_network_mode:

Host network mode ################# .. note:: Supported since Cilium 1.16+

Host network mode allows you to expose the Cilium ingress controller (Envoy listener) directly on the host network. This is useful in cases where a LoadBalancer Service is unavailable, such as in development environments or environments with cluster-external loadbalancers.

.. note:: * Enabling the Cilium ingress controller host network mode automatically disables the LoadBalancer/NodePort type Service mode. They are mutually exclusive. * The listener is exposed on all interfaces (0.0.0.0 for IPv4 and/or :: for IPv6).

Host network mode can be enabled via Helm:

.. code-block:: yaml

ingressController:
  enabled: true
  hostNetwork:
    enabled: true

Once enabled, host network ports can be specified with the following methods:

  • Shared Ingress: Globally via Helm flags
    • ingressController.hostNetwork.sharedListenerPort: Host network port to expose the Cilium ingress controller Envoy listener. The default port is 8080. If you change it, you should choose a port number higher than 1023 (see Bind to privileged port_).
  • Dedicated Ingress: Per Ingress resource via annotations
    • ingress.cilium.io/host-listener-port: Host network port to expose the Cilium ingress controller Envoy listener. The default port is 8080 but it can only be used for a single Ingress resource as it needs to be unique per Ingress resource. You should choose a port higher than 1023 (see Bind to privileged port_). This annotation is mandatory if the global Cilium ingress controller mode is configured to dedicated (ingressController.loadbalancerMode) or the ingress resource sets the ingress.cilium.io/loadbalancer-mode annotation to dedicated and multiple Ingress resources are deployed.

The default behavior regarding shared or dedicated ingress can be configured via ingressController.loadbalancerMode.

.. warning:: Be aware that misconfiguration might result in port clashes. Configure unique ports that are still available on all Cilium Nodes where Cilium ingress controller Envoy listeners are exposed.

Bind to privileged port

By default, the Cilium L7 Envoy process does not have any Linux capabilities out-of-the-box and is therefore not allowed to listen on privileged ports.

If you choose a port equal to or lower than 1023, ensure that the Helm value envoy.securityContext.capabilities.keepCapNetBindService=true is configured and to add the capability NET_BIND_SERVICE to the respective :ref:Cilium Envoy container via Helm values<envoy>:

  • Standalone DaemonSet mode: envoy.securityContext.capabilities.envoy
  • Embedded mode: securityContext.capabilities.ciliumAgent

Configure the following Helm values to allow privileged port bindings in host network mode:

.. tabs::

.. group-tab:: Standalone DaemonSet mode

  .. code-block:: yaml

      ingressController:
        enabled: true
        hostNetwork:
          enabled: true
      envoy:
        enabled: true
        securityContext:
          capabilities:
            keepCapNetBindService: true
            envoy:
            # Add NET_BIND_SERVICE to the list (keep the others!)
            - NET_BIND_SERVICE

.. group-tab:: Embedded mode

  .. code-block:: yaml

      ingressController:
        enabled: true
        hostNetwork:
          enabled: true
      envoy:
        securityContext:
          capabilities:
            keepCapNetBindService: true
      securityContext:
        capabilities:
          ciliumAgent:
          # Add NET_BIND_SERVICE to the list (keep the others!)
          - NET_BIND_SERVICE

Deploy Cilium Ingress listeners on subset of nodes

The Cilium ingress controller Envoy listener can be exposed on a specific subset of nodes. This only works in combination with the host network mode and can be configured via a node label selector in the Helm values:

.. code-block:: yaml

ingressController:
  enabled: true
  hostNetwork:
    enabled: true
    nodes:
      matchLabels:
        role: infra
        component: ingress

This will deploy the Ingress Controller Envoy listener only on the Cilium Nodes matching the configured labels. An empty selector selects all nodes and continues to expose the functionality on all Cilium nodes.

Examples ########

Please refer to one of the below examples on how to use and leverage Cilium's Ingress features:

.. toctree:: :maxdepth: 1 :glob:

http ingress-and-network-policy path-types grpc tls-termination tls-default-certificate